Nitrocellulose or similar substance and process of making same.



UNITED STATES PATENT ()FFICE.

DAVID BACHRACH, OF BALTIMORE, MARYLAND.

NITROCELLULOSE OR SIMILAR SUBSTANCE AND PROCESS OF MAKING SAME.

iil'EQIFlUATIGN forming part of Letters Patent No. 667,? 59, datedFebruary 12, 1901.

Application filed October 5, 1900. Serial No. 32,194. (No i citizen ofthe United States, residing at the city of Baltimore, in the State ofMaryland, have invented certain new and useful Impro vements inNitrocellulose and Si milar Sn bstances and Processes of Making Same,fully described and represented in the following specification, forminga part of the same.

This invention relates to improvements in nitrocellulose and similarcompounds and to a process of making the same, the object of the presentinvention being to provide a noncombustible or a very slowly combustiblecompound of this character which will be capable of use for the samepurposes as those for which celluloid, xylonite, the, are now used andalso for other purposes for which the latter, because of their highinflammability, as now made cannot be used or at least used with safety.

The present invention is based upon the discovery made by me that ifthere be added to such compounds in proper quantities a suitable saltas,for example, sulfate of li1ne-a chemical change is effected in the othersolid and ordinarily highly inflammable constituents of such compoundswhich (ac cording to the quantity of sulfate present) wholly orpartially destroys their combustibility, and thus renders the compoundas a whole non-combustible or only very slowly combustible and capableof use for the purposes above mentioned. For the production of anon-combustible compound of this character the sulfate present in thecompound, according to my invention, must constitute forty per cent. ormore (and preferably fifty per cent.) of the solid constituents of thecompound, while for the production of a compound which is not absolutelynon-combustible, but will burn only very slowlylike wood, forexample-the quantity of sulfate present may, according to my invention,be lowered to thirty per cent. The salt used may be any suitable oneformed by the addition to an antacid substance of any suitable salt-producing acid which will transform such substance into a salt; but the saltwhich I prefer and which I have found best adapt ed for the purpose issulfate of lime formed by the addition to carbonate or oxid of limeIVheu the sulfate of lime is employed and it is formed in the com pounditself, the procedure is as follows: To the usual quantities ofpyroxylin or the like and camphorten parts, by weight, of the former tofive parts, by weight, of the latteremployed in the manufacture ofcelluloid or like compounds I add ten parts or more, (and preferablyfifteen parts,) by weight, of carlmnate-of-lime pigment and a sufficientquantity of sulfuric acid to transform the carbonate into a sulfate, theusual solvent of pyroxylin being added, the quantity added dependingupon whether the compound is to be used in a fluid or solid state. Ifind that the addition of the sulfuric acid makes the substance somewhatnon-inflammable, while the addition of fifteen parts of the pigment alsobrings about a reaction which will make the product absolutelynon-combustible.

The proportions above given are for the production of a com pound whichis absolutely non-combustible. For the production of a compound which isnot absolutely non-combustible, but will onlyburn very slowlylike wood,for examplea much smaller quantity of carbonate of lime will suffice, asbefore stated.

If an acid pyroxylin be used, aless proportion of sulfuric acid will berequired than where the pyroxylin is not acid. The exact amount can bedetermined in each case by experiment.

If the sulfate pigments be previously prepared and added direct to theother ingredients without the chemical reaction produced by theadmixture separately with the other constituents of the carbonate andacid, as described, a non-inflammable substance will also be produced;but in this case a much larger proportion of sulfate will be required,which will deprive the product of some of its flexibility desirable forcertain purposes, the quantity of sulfate required in such case being'sixty per cent. or more, by weight, of the solid constituents of theproduct to make it non-inflammable. I have found that somewhat similarresults are produced by the use of other pigments, such as phosphate oflime or any pigment or salt that is changed by reaction in the compoundto a sulfate or salt corresponding to the acid used in the addition. Itis this reaction in the compound itself and the large proportions hereingiven that produce the property of non-inflammability which is thesubject of my invention.

What I claim is- 1. A nitrocellulose or similar compound containing asulfate constituting thirty per cent. or more by Weight of the solidconstitucuts of the compound.

2. The process of forming a non-combustible cellulose or similarcompound which con- DAVID BACHRAOH.

Witnesses:

NELLIE HANNA, ARCHIE J. WILLIAMS.

